1. Field of the Invention
The present invention relates to fan control in a computer cooling system.
2. Background of the Related Art
Computers consume electrical energy and generate heat. Many computers include fans to generate airflow for removing heat. Removing heat from a computer helps control internal temperatures, to maintain system reliability, performance, and longevity. Rack-mounted computers typically include several servers and other equipment in a high-density arrangement within a chassis, thus generating the combined heat of the servers and other equipment in the chassis. A blower module may be provided in the chassis external to the servers, having several fans to generate the large amount of airflow through the chassis required to cool the servers. In a data center, the heated exhaust air from a rack may be transported to a computer-room air conditioner (“CRAC”), which cools the air before returning the cooled air to the data center. Energy efficiency in a datacenter dramatically affects the total cost of ownership of datacenter equipment.
Server systems are often designed around a particular set of design objectives. While performance and efficiency are both desirable objectives, a particular system will typically emphasize or prioritize one objective over the other. For example, some market segments choose to focus on energy efficiency, such that performance is not the primary focus. Conversely, other market segments emphasize performance as paramount over energy efficiency. However, there is a clear trade-off between energy efficiency and performance. A performance-focused system imposes greater cooling demands, often using more exotic technologies, with higher-cost fan models. A system focused on energy efficiency may be implemented with comparatively less expensive and lower-power fan models.